Search tips
Search criteria

Results 1-10 (10)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Identification and Comparative Analysis of Hepatitis C Virus-Host Cell Protein Interactions 
Molecular bioSystems  2013;9(12):3199-3209.
Hepatitis C virus (HCV) alters the global behavior of the host cell to create an environment conducive to its own replication, but much remains unknown about how HCV proteins elicit these changes. Thus, a better understanding of the interface between the virus and host cell is required. Here we report the results of a large-scale yeast two-hybrid screen to identify protein-protein interactions between HCV genotype 2a (strain JFH1) and cellular factors. Our study identified 112 unique interactions between 7 HCV and 94 human proteins, over 40% of which have been linked to HCV infection by other studies. These interactions develop a more complete picture of HCV infection, providing insight into HCV manipulation of pathways, such as lipid and cholesterol metabolism, that were previously linked to HCV infection and implicating novel targets within microtubule-organizing centers, the complement system and cell cycle regulatory machinery. In an effort to understand the relationship between HCV and related viruses, we compared the HCV 2a interactome to those of other HCV genotypes and to the related dengue virus. Greater overlap was observed between HCV and dengue virus targets than between HCV genotypes, demonstrating the value of parallel screening approaches when comparing virus-host cell interactomes. Using siRNAs to inhibit expression of cellular proteins, we found that five of the ten shared targets tested (CUL7, PCM1, RILPL2, RNASET2, and TCF7L2) were required for replication of both HCV and dengue virus. These shared interactions provide insight into common features of the viral life cycles of the family Flaviviridae.
PMCID: PMC4171131  PMID: 24136289
virus-host cell; dengue; interactome; yeast two-hybrid; microtubule organizing center
2.  Isolating the Contributions of Familiarity and Source Information to Item Recognition: A Time Course Analysis 
Recognition memory may be mediated by the retrieval of distinct types of information, notably, a general assessment of familiarity and the recovery of specific source information. A response-signal speed–accuracy trade-off variant of an exclusion procedure was used to isolate the retrieval time course for familiarity and source information. In 2 experiments, participants studied spoken and read lists (with various numbers of presentations) and then performed an exclusion task, judging an item as old only if it was in the heard list. Dual-process fits of the time course data indicated that familiarity information typically is retrieved before source information. The implications that these data have for models of recognition, including dual-process and global memory models, are discussed.
PMCID: PMC3313826  PMID: 10368927
3.  Role of Nrf2 in prevention of high-fat diet-induced obesity by synthetic triterpenoid CDDO-Imidazolide 
European journal of pharmacology  2009;620(1-3):138-144.
The synthetic oleanolic triterpenoid 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Imidazolide or CDDO-Im) is an extremely potent activator of Nrf2 signaling. In cells undergoing adipogenesis, CDDO-Im prevents lipid accumulation in an Nrf2-dependent manner. However, in vivo evidence for effects of CDDO-Im on obesity is lacking. The goals of these studies were to determine if CDDO-Im can prevent high-fat diet-induced obesogenesis in the mouse, and to elucidate the molecular target of drug action. Wild-type and Nrf2-disrupted C57BL/6J female mice were dosed 3 times per week with 30 μmol/kg CDDO-Im or vehicle by oral gavage, during 95 days of access to a control diet or a high-fat diet. Body weights, organ weights, hepatic fat accumulation and gene expression were measured. Treatment with CDDO-Im effectively prevented high-fat diet-induced increases in body weight, adipose mass, and hepatic lipid accumulation in wild-type mice but not in Nrf2-disrupted mice. Wild-type mice on a high-fat diet and treated with CDDO-Im exhibited higher oxygen consumption and energy expenditure than vehicle-treated mice, while food intake was lower in CDDO-Im-treated than vehicle-treated mice. Levels of gene transcripts for fatty acid synthesis enzymes were downregulated after CDDO-Im treatment in the liver of wild-type mice. This inhibitory effect of CDDO-Im on lipogenic gene expression was significantly reduced in Nrf2-disrupted mice. The results indicate that CDDO-Im is an exceedingly potent agent for preventing obesity, and identify the Nrf2 pathway as a novel target for management of obesogenesis.
PMCID: PMC2752754  PMID: 19698707
Nrf2; Diet-induced obesity; Fatty acid synthase; Triterpenoid
4.  Novel Alkyl Side Chain Sulfone 1α,25-Dihydroxyvitamin D3 Analogs: A Comparison of in vitro Antiproliferative Activities and in vivo Calcemic Activities 
Bioorganic & medicinal chemistry  2009;17(15):5627-5631.
The replacement of a t-butyl group with a trifluoromethyl group has profound effects on the biological profile of 1α,25-dihydroxyvitamin D3 sulfone analogs. Investigation of whether the improved biological activities are due to steric and electronic factors of the trifluoromethyl group led to the design, synthesis and biological evaluation of two analogous alkyl sulfone molecules, methyl sulfone (AU-16-ene-25-SO2-CH3) and isopropyl sulfone (AU-16-ene-25-SO2-i-Pr). These alkyl sulfones are sterically comparable to, but electronically very different from a trifluoromethyl group. The syntheses, antiproliferative activities and calcemic activities of these new alkyl sulfones are presented herein. In comparing the in vitro antiproliferative profiles of the new alkyl sulfone 1α,25-dihydroxyvitamin D3 analogs with the trifluoromethylsulfone and an analogous t-butyl sulfone, the activities increase in the following order: CH3
PMCID: PMC2713797  PMID: 19577932
Carcinogenesis  2009;30(6):1024-1031.
Loss of NF-E2-related factor 2 (Nrf2) signaling increases susceptibility to acute toxicity, inflammation and carcinogenesis in mice due to the inability to mount adaptive responses. In contrast, disruption of Keap1 (a cytoplasmic modifier of Nrf2 turnover) protects against these stresses in mice, although inactivating mutations in Keap1 have been identified recently in some human cancers. Global characterization of Nrf2 activation is important to exploit this pathway for chemoprevention in healthy, yet at-risk individuals and also to elucidate the consequences of hijacking the pathway in Keap1-mutant human cancers. Liver-targeted conditional Keap1-null, Albumin-Cre:Keap1(flox/−) (CKO) mice provide a model of genetic activation of Nrf2 signaling. By coupling global gene expression analysis of CKO mice with analysis of pharmacologic activation using the synthetic oleanane triterpenoid 1-[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im), we are able to gain insight into pathways affected by Nrf2 activation. CDDO-Im is an extremely potent activator of Nrf2 signaling. CKO mice were used to identify genes modulated by genetic activation of Nrf2 signaling. The CKO response was compared with hepatic global gene expression changes in wild-type mice treated with CDDO-Im at a maximal Nrf2 activating dose. The results show that genetic and pharmacologic activation of Nrf2 signaling modulates pathways beyond detoxication and cytoprotection, with the largest cluster of genes associated with lipid metabolism. Genetic activation of Nrf2 results in much larger numbers of detoxication and lipid metabolism gene changes. Additionally, analysis of pharmacologic activation suggests that Nrf2 is the primary mediator of CDDO-Im activity, though other cell-signaling targets are also modulated following an oral dose of 30 μmol/kg.
PMCID: PMC2691141  PMID: 19386581
Three new vitamin D analogs 3-5 incorporating a –CHF2 group as an –OH surrogate have been prepared. Two of these new analogs (3 and 5) are strongly antiproliferative toward murine keratinocytes and are approximately 50 times less calciuric in vivo than the natural hormone calcitriol. The transcriptional activity of the 25-CHF2 analog 3 is higher than that of the 1-CHF2 analog 4.
PMCID: PMC2712873  PMID: 17218093
Fluorinated D analogs; growth inhibition; low-calcemic; protease digestion assay; VDR-binding
Oxidative stress-mediated destruction of normal parenchymal cells during hepatic inflammatory responses contributes to the pathogenesis of immune-mediated hepatitis and is implicated in the progression of acute inflammatory liver injury to chronic inflammatory liver disease. The transcription factor NF-E2-related factor 2 (Nrf2) regulates the expression of a battery of antioxidative enzymes and Nrf2 signaling can be activated by small-molecule drugs that disrupt Keap1-mediated repression of Nrf2 signaling. Therefore, genetic and pharmacologic approaches were used to activate Nrf2 signaling to assess protection against inflammatory liver injury. Profound increases in ind of cell death were observed in both Nrf2 wild-type (Nrf2-WT) mice and Nrf2-disrupted (Nrf2-KO) mice 24-hr following intravenous injection of concanavalin A (12.5 mg/kg, ConA), a model for T cell-mediated acute inflammatory liver injury. However, hepatocyte-specific conditional Keap1 null (Alb-Cre:Keap1flox/−, cKeap1-KO) mice with constitutively enhanced expression of Nrf2-regulated antioxidative genes as well as Nrf2-WT mice but not Nrf2-KO mice pretreated with three daily doses of a triterpenoid that potently activates Nrf2 (30 µmole/kg, CDDO-Im) were highly resistant to ConA-mediated inflammatory liver injury. CDDO-Im pretreatment of both Nrf2-WT and Nrf2-KO mice resulted in equivalent suppression of serum pro-inflammatory soluble proteins suggesting that the hepatoprotection afforded by CDDO-Im pretreatment of Nrf2-WT mice but not Nrf2-KO mice was not due to suppression of systemic pro-inflammatory signaling, but instead was due to activation of Nrf2 signaling in the liver. Enhanced hepatic expression of Nrf2-regulated antioxidative genes inhibited inflammation-mediated oxidative stress, thereby preventing hepatocyte necrosis. Attenuation of hepatocyte death in cKeap1-KO mice and CDDO-Im pretreated Nrf2-WT mice resulted in decreased late-phase pro-inflammatory gene expression in the liver thereby diminishing the sustained influx of inflammatory cells initially stimulated by the ConA challenge. Taken together, these results clearly illustrate that targeted cytoprotection of hepatocytes through Nrf2 signaling during inflammation prevents the amplification of inflammatory responses in the liver.
PMCID: PMC2435415  PMID: 18417483
Liver inflammation; Nrf2; Keap1; antioxidative enzymes; cytoprotection; triterpenoid
Bioorganic & medicinal chemistry  2007;15(16):5509-5518.
Novel fluorinated sulfone analogs of the hormone 1α,25-dihydroxyvitamin D3 have been designed and synthesized in order to study the biological effects of fluorine incorporation at the terminus of the C,D-ring side chain. Although biologically active 26,27-hexafluorinated 1α,25-dihydroxyvitamin D3 analogs have been synthesized previously, this investigation reports the first successful fluorinated series in which trifluoromethyl sulfone analogs present a favorable biological profile. This study shows that two new analogs featuring incorporation of a synthetically simple single trifluoromethyl sulfone group have significantly increased antiproliferative activity while causing desirably low in vivo calciuria relative to that of calcitriol. Incorporation of additional fluorines, as in a perfluorobutyl analog, results in a loss of antiproliferative activity.
PMCID: PMC2586064  PMID: 17560112
The Journal of biological chemistry  2006;282(3):1585-1594.
APOBEC3G and APOBEC3F are cytidine deaminase with duplicative cytidine deaminase motifs that restrict HIV-1 replication by catalyzing C-to-U transitions on nascent viral cDNA. Despite 60% protein sequence similarity, APOBEC3F and APOBEC3G have a different target consensus sequence for editing, and importantly, APOBEC3G has 10-fold higher anti-HIV activity than APOBEC3F. Thus, APOBEC3F and APOBEC3G may have distinctive characteristics that account for their functional differences. Here, we have biochemically characterized human APOBEC3F and APOBEC3G protein complexes as a function of the HIV-1 life cycle. APOBEC3G was previously shown to form RNase-sensitive, enzymatically inactive, high molecular mass complexes in immortalized cells, which are converted into enzymatically active, low molecular mass complexes by RNase digestion. We found that APOBEC3F also formed high molecular mass complexes in these cells, but these complexes were resistant to RNase treatment. Further, the N-terminal half determined RNase sensitivity and was necessary for the high molecular mass complex assembly of APOBEC3G but not APOBEC3F. Unlike APOBEC3F, APOBEC3G strongly interacted with cellular proteins via disulfide bonds. Inside virions, both APOBEC3F and APOBEC3G were found in viral cores, but APOBEC3G was associated with low molecular mass, whereas APOBEC3F was still retained in high molecular mass complexes. After cell entry, both APOBEC3F and APOBEC3G were localized in low molecular mass complexes associated with viral reverse transcriptional machinery. These results demonstrate that APOBEC3F and APOBEC3G complexes undergo dynamic conversion during HIV-1 infection and also reveal biochemical differences that likely determine their different anti-HIV-1 activity.
PMCID: PMC1880894  PMID: 17142455
Anesthesia Progress  1988;35(2):53-60.
Pulse oximetry has been shown to be accurate under steady state conditions. In this study, the accuracy of four pulse oximeters are evaluated and compared during outpatient general anesthesia for third molar extractions. The oximeters evaluated are the Nellcor N-100, the Ohmeda 3700, the Novametrix model 500, and the Bird 4400 portable pulse oximeter.
Ultralight general anesthesia for oral surgery presents a unique challenge for respiratory monitoring in that patients are often not intubated and commonly experience periods of hyper- and hypoventilation. Airway obstruction, apnea, and laryngospasm may occur easily and patients often vocalize and move during surgery. Because hypoxemia is the primary cause of morbidity and mortality during anesthesia, an accurate, continuous, and noninvasive monitor of oxygenation is critical to risk management.
Twenty ASA class I and II patients underwent outpatient general anesthesia for third molar removal using nitrous oxide-oxygen, midazolam, fentanyl, and methohexital. Arterial blood samples were obtained at five-minute intervals during anesthesia, as well as any time a desaturation of >5% occurred, for measurement of arterial SaO2 with an IL282 CO-Oximeter. These values were compared with simultaneously recorded saturations observed for each pulse oximeter. A total of 122 arterial samples were obtained over a range of PaO2 from 52-323 mm Hg and observed saturations of 70-100%.
The Bird 4400 portable pulse oximeter proved to be the most accurate and reliably predicted arterial saturation under these conditions (y = 1.03x - 2.8, r = 0.85). The Novametrix model 500 pulse oximeter also demonstrated a high degree of accuracy by linear regression analysis, but displayed the lowest correlation coefficient (spread of data points) overall (y = 0.97x + 2.8, r = 0.80.) The Nellcor N-100 pulse oximeter also proved to be highly accurate. (y = 1.05x - 4.1, r = 0.84.) In contrast, regression analysis of the observed saturations obtained with the Ohmeda 3700 pulse oximeter revealed that this unit significantly underestimated arterial saturation (y = 1.20x - 19.6, r = 0.83.)
This study demonstrates that despite the rigorous conditions imposed by outpatient general anesthesia for oral surgery, three of the pulse oximeters tested were linearly accurate in predicting arterial oxyhemoglobin saturation over the range of 70-100%. The Ohmeda 3700 was found to significantly underestimate arterial saturation.
PMCID: PMC2148593  PMID: 3166346

Results 1-10 (10)